Modern Vespa

My LX150 is dying (slowly) at idle but riding great otherwise. The air filter looks clean, I have oil and this still happens if I unplug the secondary air system. Other then checking the idle (I don't have a tach) is there anything else I should be looking for?

It may or may not be relevant but it just got cold here. I rode yesterday (when it was colder) without problems though.

Do you mean that unless you are giving the scooter some gas, it just dies, or that the scooter idles and then slowly sputters and stops?

Basically this morning I started it up and went inside to let the engine warm up. I then put on my gear and hopped on it and rode away. The engine was running just fine. When I went the six blocks to the first stop light and came to a stop the engine idled for a minute, sputtered and died. From that point on if I let it idle it would sputter and die. I made it home and put the scoot away.

Now after work I came home and checked the SAS and air filter (both okay as far as I can tell) and tried to start it up again. Same thing, starts up and idles fine while warming up, then dies at idle. If I hold the throttle open just a tiny crack it will be fine.

I can't help you with that one, I'm afraid. I had the problem with the scooter dying immediately unless you keep giving it a little gas while idling. Doesn't seem to be the same situation that you have. Sorry.

When that happened to me, I just bumped up the idle a bit and it stopped happening.

it's not uncommon to have to adjust the idle speed a few times a year, as the air temperature changes.

sounds like a clogged idle jet. thats what happened to both my wife and I one time.

Do you just run cleaner through the engine or what?

My first thought was just to increase the idle but I didn't want to be covering up another potential problem.

Actually the vespa dealer took the carb loose and rotated it ( still on the manifold) until the bowl was pointing up. He took the bowl and float off and pushed a tiny steel wire thru the jet. He used a steel wire off a small wire brush and its diameter was really tiny.

Well I don't know if it is because the weather warmed up or because I turned the idle screw 1/8 clockwise but it runs great now. I'll probably run it tomorrow morning when it's cold to make sure.

Might be a dirty jet, but more likely bumping up your revs will be the fix (at least it was for me when I had the same happen). Also, be sure you are warming up your bike longer than usual now that its cold out.